<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>数据类型</title>
    <script>
        function f1(){
            let i = 1;
            console.log(i);
            console.log(typeof i);
            i = "admin";
            console.log(i);
            console.log(typeof(i));
            i = 3.14;
            console.log(i)
            console.log(typeof i);
            i = true;
            console.log(i)
            console.log(typeof i);

            let name;
            console.log(name);
            name = null;
            console.log(name);
            name = "admin";
            name = parseInt(name);
            // NaN:Not a Number
            console.log(name);

            let arr = [1,2,3];
            console.log(arr);
            console.log(typeof arr);
        }
    </script>
</head>
<body>
<button onclick="f1()">测试</button>
</body>
</html>